Defecography: What It Is, What the Test Is Like, What It Diagnoses, and What to Expect — What You Need to Know
Updated: 2 days ago
Medically reviewed by Dr. Baraa Alnahhal, MD · Last reviewed: September 2026
Quick Answer
Defecography is a radiology test that lets healthcare providers watch your muscles and organs in action while you poop (defecate). It's done with fluoroscopic X-ray or MRI imaging. You don't pass real stool — your rectum is filled with a barium paste that has the same consistency as poop, and you evacuate it on a special toilet inside the scanning machine while a radiologist watches on a computer screen. The test takes about 30 to 60 minutes, isn't painful, and helps diagnose causes of constipation, fecal incontinence, incomplete evacuation, pelvic floor dysfunction, and organ prolapse.
TL;DR
If bathroom problems like constipation, uncontrolled pooping (fecal incontinence), anal pain, or the feeling that you never fully empty have gone unexplained for a while, your provider may order a defecography — a "pooping study" that films your pelvic floor muscles, anus, colon, rectum, vagina, and bladder in real time. The test uses either a fluoroscopic X-ray (a video X-ray with a small amount of radiation) or MRI (no radiation). Barium paste replaces stool, and the radiologist watches screens, not you. The test takes 30–60 minutes, feels demanding or awkward at times but isn't painful, and usually leads directly to a better treatment plan or surgical planning.
Limitation note: This article draws on a single clinical source, which provides no statistics on test accuracy, condition prevalence, or outcomes. No numerical claims are presented here.
What is a defecography?
If you're having trouble pooping — or holding in your poop — or experiencing any kind of unwanted sensation when you poop, your healthcare provider may recommend defecography to find out what the problem is. Defecography is a radiology test to look inside at your muscles and organs while you poop (defecate). Through detailed fluoroscopic X-ray or magnetic resonance imaging (MRI), healthcare providers can see how different muscles and organs are moving when you poop.
Here's the part that surprises most people: you don't actually poop real poop in the test. Healthcare technicians fill your rectum with a barium paste — a medical substance with the same consistency as poop. Barium is a contrast agent that makes your insides show up better in X-ray or MRI tests. You'll evacuate the paste on a special toilet inside a scanning machine. The radiologist will be looking at your insides on a computer screen, not at you squatting on the toilet.
When would this procedure be needed?
The purpose of the test is to give your healthcare provider more information about how things are working when you poop, in order to diagnose and treat your problem. Your provider may need to see:
What Providers Look For | What It Reveals |
Pelvic floor muscle movement | How muscles contract and relax |
Anus function | How it functions when poop is present |
Organ movement | How the colon, rectum, vagina, and bladder move while pooping |
Organ position | Whether any internal organs are out of place |
Surgical planning | What needs to be addressed in a planned surgery |
What conditions does this test diagnose?
Your healthcare provider may recommend a defecography to help determine the cause of longstanding unexplained symptoms when you poop, such as:
Symptom | What It Means |
Anal pain | Pain in or around the anus |
Constipation | Difficulty pooping |
Fecal incontinence | Uncontrolled pooping |
Incomplete evacuation | The feeling that you didn't poop everything out |
They may also use the test to help diagnose a suspected condition, such as:
Pelvic floor dysfunction — a failure of the muscles and nerves in the pelvic floor to coordinate and move properly when you poop.
Organ prolapse — when the wall of one of your organs has weakened enough to fall out of place, or one organ is bulging into another organ. The main types include:
Prolapse Type | What Happens |
Rectal prolapse | The rectum slips out of the anus |
Rectocele | The rectum bulges into the vagina |
Enterocele | The small intestines bulge into the rectum |
Who performs this procedure?
All X-ray and MRI exams are performed by certified radiologists specially trained to operate and interpret the test results. Defecography in particular is performed by a specialist experienced in understanding anorectal motility.
How does the test work?
Defecography can be done by fluoroscopic X-ray or by MRI. Both kinds of imaging can visualize the inside mechanics of your body as you poop. X-ray is more commonly used, but some people may need to avoid the small radiation exposure that it produces.
A fluoroscopic X-ray is like a video X-ray. Instead of taking isolated snapshots, fluoroscopy passes a continuous X-ray beam through the body, producing continuous images on a screen in real time. Rather than developing photographs, healthcare providers can view a video of your organs in action.
MRI (magnetic resonance imaging) works with radio waves and a magnetic field. Metal coils throughout the machine produce a magnetic field through electric current, which moves hydrogen atoms in your body. As they move back into place, they transmit a signal that the machine interprets through radio waves, producing an image on a computer.
What happens before the test?
Your healthcare provider will carefully record your medical history, including relevant surgeries and conditions, medications you take, and implants you may have. They'll ask you to describe in detail exactly what happens when you poop.
Then they'll describe the procedure in detail and explain how you can collaborate during the test to help achieve the clearest results. The success of the test depends on your cooperation.
Your provider may give you an enema to take at home to clear out your bowels before the test. They may also ask you to modify your diet, medications, and water intake before the test. Guidelines vary, so follow the advice of your provider.
How will I be prepared on the day of the test?
Whether you're having a fluoroscopic X-ray defecography or an MRI defecography, both tests require some kind of contrast agent to highlight the internal organs your provider wants to see — and that contrast agent has to get inside you before the test.
To visualize the last part of your digestive tract — the colon, rectum, and anus — your healthcare team prepares the agent (barium sulfate) as a paste to put into your anus. You'll receive the barium enema immediately before the test. However, your provider may want to see other organs that the enema can't reach:
If They Need to See | How It's Done |
Small intestine | Swallow a contrast solution, possibly several hours before the test to let it travel |
The wall between the vagina and anus | Barium paste applied to your vagina |
What should I expect during a defecography test?
After changing into a hospital gown, you'll proceed to the testing room and lie on a table. Your healthcare team will inject barium paste into your anus with something resembling a caulking gun. You may feel mild bloating or cramping from the enema. When your anus is full, you'll feel the natural urge to defecate, and you'll be ready for the test.
Setting up to go: If you're in an X-ray machine or an open MRI machine, your table will tilt vertically and a special toilet will be placed beneath you — you'll sit on the toilet as you normally would. Both machines have an open and airy design to prevent feelings of claustrophobia. If you're in a traditional MRI machine, which is more like a tube, you'll remain horizontal on the table and poop into an adult diaper. A blanket with metal coils inside may be placed over you.
Managing comfort: Some people feel claustrophobic inside a traditional MRI machine. You can ask for sedative medication to help you relax. The machine is well-lit and air-conditioned, and you can speak to your technician through an intercom. Both open and traditional MRI machines make loud popping and clicking noises while recording images — you'll be offered earplugs or headphones in advance.
During the recording: The radiologist operating the test equipment will give you instructions from outside the unit, telling you when to squeeze, hold, and relax your muscles as images are recorded. You'll need to use enough force so the technician can clearly see how your muscles engage when you push, and you'll remain very still while each series of pictures is taken — usually for less than a minute.
The whole thing takes about 30 to 60 minutes. It might feel demanding or embarrassing, but it isn't painful.
What can I expect after the test?
After the test, you'll be brought to a private restroom where you can wash up. You may continue to see the white, chalky barium in your poop for the next day or so. You can resume your normal activities and diet immediately.
What are the risks or side effects of the test?
The small amount of radiation exposure from X-ray is considered safe, as long as it isn't a regular occurrence. MRI poses no risks or side effects. If you are pregnant, it's standard practice to avoid both tests, if possible — even though the risk of harm to the fetus is very small.
What type of results will I get, and what do they mean?
The radiologist will send a detailed report to your primary healthcare provider, who will share the results with you. The report will reveal or rule out standard defecating disorders and address any specific concerns your provider inquired into.
A note from the clinical source: "If your healthcare provider has suggested a pooping study, chances are you've been having a difficult time with pooping for a while. Your defecography can provide essential information for your healthcare provider so that they can come up with the best plan of care to improve your pooping experience. It's a little awkward, but if it leads to a successful diagnosis and treatment, it may bring relief in the end."
When should I talk to my healthcare provider about this test?
A defecography is always provider-ordered — you don't request it yourself. If you've been dealing with constipation, uncontrolled pooping, anal pain, or the persistent feeling of incomplete emptying, and simpler treatments haven't explained or fixed the problem, ask your provider whether a defecating study could be the right next step. If you're pregnant or think you might be, tell your provider, since both test types are typically avoided during pregnancy even though the fetal risk is very small.
Conclusion: An awkward test that can finally explain your symptoms
Defecography has a reputation for being one of the most unusual tests in medicine — but for people who've struggled with bathroom problems for years, it's often the first time anyone actually watches how the problem happens. By filming your pelvic floor, anus, colon, rectum, vagina, and bladder in real time, it can pinpoint pelvic floor dysfunction and organ prolapse (rectal prolapse, rectocele, enterocele) that no other test catches, and it tells surgeons exactly what needs to be fixed.
The practical realities are manageable: no real stool is involved (barium paste does the job), the radiologist watches screens rather than you, MRI carries no radiation, the test takes 30–60 minutes and isn't painful, and you can return to normal life immediately afterward. Awkward, yes — but as the clinical source puts it, if it leads to a successful diagnosis and treatment, it may bring relief in the end.
Your next step: If longstanding constipation, incontinence, or incomplete emptying hasn't responded to simpler measures, ask your healthcare provider whether a defecography would help explain what's happening — and follow their prep instructions exactly, since the test's success depends on your cooperation.
Frequently Asked Questions (FAQ)
What is a defecography?
A defecography is a radiology test that lets healthcare providers look inside at your muscles and organs while you poop (defecate), using fluoroscopic X-ray or MRI imaging.
Is a defecography painful?
No. The test might feel demanding or embarrassing, but it isn't painful. You may feel mild bloating or cramping from the barium enema.
Do you really poop during the test?
Not real stool. Technicians fill your rectum with barium paste that has the same consistency as poop, and you evacuate it on a special toilet inside the scanning machine.
Is it embarrassing?
It can feel awkward — but the radiologist watches your insides on a computer screen, not you squatting on the toilet. Machines are open and airy, and you can ask for sedation if claustrophobic.
What is the barium paste?
A contrast agent (barium sulfate) with the same consistency as poop. It makes your insides show up clearly on X-ray or MRI images.
How is the barium paste given?
Your healthcare team injects it into your anus with something resembling a caulking gun, immediately before the test, as a barium enema.
How long does a defecography take?
About 30 to 60 minutes, including setup, imaging series, and cleanup.
Is a defecography an X-ray or an MRI?
It can be either — fluoroscopic X-ray (a "video X-ray" with continuous real-time images) or MRI (radio waves and a magnetic field, no radiation). X-ray is more commonly used.
Does the test use radiation?
Only the X-ray version, and the amount is small and considered safe as long as it isn't a regular occurrence. MRI poses no radiation risk.
Can I have a defecography if I'm pregnant?
Standard practice is to avoid both test types during pregnancy, if possible — even though the risk of harm to the fetus is very small.
What conditions does a defecography diagnose?
It helps determine the causes of constipation, fecal incontinence, anal pain, and incomplete evacuation, and can diagnose pelvic floor dysfunction and organ prolapse (rectal prolapse, rectocele, enterocele).
What is pelvic floor dysfunction?
A failure of the muscles and nerves in the pelvic floor to coordinate and move properly when you poop.
What is a rectocele?
When the rectum bulges into the vagina — one type of organ prolapse a defecography can detect.
What is an enterocele?
When the small intestines bulge into the rectum — another prolapse type detectable on defecography.
What is incomplete evacuation?
The feeling that you didn't poop everything out — a symptom that may prompt a defecography.
How do I prepare for the test?
Your provider records your medical history, may give you an at-home enema to clear your bowels, and may ask you to modify your diet, medications, and water intake. Guidelines vary — follow your provider's advice.
Do they put barium anywhere else?
If they need to see your small intestine, you may swallow a contrast solution hours before the test. To see the wall between your vagina and anus, barium paste may be applied to your vagina.
What happens during the test?
After the barium enema, you sit on a special toilet in an X-ray or open MRI machine (or lie horizontal in a tube MRI and use an adult diaper). The radiologist instructs you when to squeeze, hold, and relax while images are recorded. Each still series lasts less than a minute.
What if I'm claustrophobic?
You can ask for sedative medication. Machines are well-lit and air-conditioned, you can talk to the technician through an intercom, and earplugs or headphones are offered for the loud popping and clicking noises.
Can I eat and do normal things afterward?
Yes — you can resume normal activities and diet immediately. White, chalky barium may appear in your poop for the next day or so.
Who performs the test?
Certified radiologists specially trained to operate and interpret the results, with defecography performed by a specialist experienced in anorectal motility.
How do I get my results?
The radiologist sends a detailed report to your primary healthcare provider, who shares the results with you. The report reveals or rules out standard defecating disorders.
Why would my provider order this test?
To see how your pelvic floor muscles contract and relax, how your anus functions, how your colon, rectum, vagina, and bladder move, whether organs are out of place, and what needs addressing in planned surgery.
Does the test need my cooperation to work?
Yes — the success of the test depends on your cooperation, including using enough force when pushing and staying very still during each image series.
What happens if I can't push enough?
You'll be instructed to use enough force so the technician can clearly see how your muscles engage; communicating openly with the team helps them get usable images.
Who should talk to their provider about this test?
Anyone with longstanding, unexplained bathroom problems — difficulty pooping, uncontrolled pooping, anal pain, or feeling of incomplete emptying — whose simpler treatments haven't resolved the issue.
External References
Cleveland Clinic — Defecography (primary source, medically reviewed, last updated Jan 10, 2022)
Disclaimer: This article is for general educational purposes only and does not constitute medical advice. It is based on a single referenced clinical source and should not replace professional diagnosis or treatment. Talk to your healthcare provider about whether a defecography is appropriate for your situation, especially if you are or might be pregnant.
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